There is presently no satisfactory vaccine for immunization against Asiatic cholera, a disease of man which has existed for years in many nations of Europe, Asia, and Africa. As judged from the literature on human cholera and studies in animal models, it presently can be argued that the important components of induced immunity should be both antibacterial and antitoxic in nature, and mucosal in origin. However, relatively little basic information is available on the nature, loci, and kinetics of the immune responses in animal models. We therefore propose continuation of detailed kinetics studies of the systemic and intestinal immune responses in experimental cholera in which antivibrio and antitoxic responses will be studied at the organ and cellular levels. A study of this nature has recently become feasible with the development of a suitable animal model, the chinchilla, and the availability of highly purified cholera toxin. We believe that information thus obtained will significantly apply to improving procedures for immunizing man against this, and possibly other, mucosa- associated diseases. By extension, the basic information to be sought in this study would also be useful in interpreting other host-parasite systems where the invader is, in effect, "outside the body."